Processing voice signals in a linear predictive coding (LPC) system provides certain information which specifically decribes the voice signal being processed. Part of the information required to specifically describe the voice signal is a quantity referred to as the pitch. In LPC systems the pitch is determined by means of an absolute magnitude difference function (AMDF) generator or analyzer, the operation of which will be described in more detail presently.
In the prior art, integrated circuits formed on a single semiconductor chip generally contain only a single arithmetic logic unit (ALU) and signals are passed through the ALU a number of times to provide a single function. This prior art apparatus and method of providing certain arithmetic functions is very slow and, in voice processing systems may be too slow.